POS1050 INCIDENCE RATES OF INTERSTITIAL LUNG DISEASE AMONG PATIENTS WITH RHEUMATOID ARTHRITIS TREATED WITH ABATACEPT: A POST HOC POOLED ANALYSIS FROM A COMPENDIUM OF CLINICAL TRIALS
Authors: P. Dieudé, J. Sparks, A. Fischer, L. Chen, K. Lozenski, S. Dahan, M. Chaballa, W. Little
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Interstitial lung disease (ILD) is a recognized complication of RA. Prior studies have suggested stabilization or improvement of ILD in patients with RA (RA-ILD) treated with abatacept.<sup>[1,2]</sup> Few studies have evaluated the background incidence rate of RA-ILD. <h3>Objectives</h3> To determine the incidence rate of clinically significant ILD in a cohort of patients with RA receiving abatacept + MTX versus placebo + MTX from multiple clinical trials. <h3>Methods</h3> This retrospective analysis examined pooled safety data from ten phase 3 clinical trials of patients with RA treated with background MTX in combination with abatacept or placebo. The term 'interstitial lung' was used to identify incidences of ILD reported as AEs in the safety data. The exposure period for each patient was censored at first incidence of clinically significant ILD, 56 days after last study drug administration, or 1 day prior to commencement of another study drug, whichever occurred first. Poisson regression models were used to estimate crude incidence rates per 100 person-years for baseline risk factors within treatment groups, and to estimate incidence rate ratios for the placebo + MTX versus abatacept + MTX treatment groups. Disease activity parameters, DAS28 (CRP) and HAQ-DI, were estimated from baseline to the time of ILD diagnosis (as reported by AEs). <h3>Results</h3> In total, 3,708 patients (10,521 person-years) treated with abatacept + MTX and 999 patients (938 person-years) treated with placebo + MTX were included. Patients treated with placebo + MTX had a higher incidence rate of ILD per 100 person-years (95% CI) versus those treated with abatacept + MTX (0.43 [0.16–1.14] vs 0.10 [0.05–0.18], respectively; Figure 1). The incidence rate ratio of placebo + MTX versus abatacept + MTX treatment groups for the total population was 4.49 (95% CI, 1.23–13.42). For all subpopulations stratified by baseline risk factors (where ≥ 1 patient in each treatment group had an ILD event), incidence rate ratios were &gt; 2. Patients with RA aged ≥ 55 years, BMI &lt; 30 kg/m<sup>2</sup>, no history of smoking, no baseline DMARD use other than MTX, no prior TNF inhibitor use, corticosteroid use, high DAS28 (CRP) status, and RF or anti-citrullinated protein antibody (ACPA) positivity were all significantly less likely to develop ILD if treated with abatacept + MTX versus placebo + MTX (Figure 1). <h3>Conclusion</h3> Incidence rates of ILD among patients with RA were significantly lower in those treated with abatacept + MTX than placebo + MTX, both in the total analysis population and subpopulations stratified by baseline risk factors. This suggests a possible protective benefit of abatacept on the incidence rate of RA-ILD. Limitations of this post hoc analysis include the different observation period lengths of the 2 treatment arms due to the original study designs, and the low number of patients with ILD events overall. However, the low incidence rate of ILD observed here is consistent with previously reported studies.<sup>[3]</sup> <h3>References</h3> [1] Mena-Vázquez N, et al. <i>Biomedicines</i> 2022;10:1480. [2] Fernández-Díaz C, et al. <i>Rheumatology</i> 2020;59:3906–3916. [3] Curtis JR, et al. <i>Arthritis Res Ther</i> 2015;17:319. <h3>Acknowledgements</h3> This study was sponsored by Bristol Myers Squibb. Professional medical writing and editorial assistance was provided by Ellen Seeley, MSc, of Caudex, and was funded by Bristol Myers Squibb. <h3>Disclosure of Interests</h3> Philippe Dieudé Speakers bureau: AbbVie, Boehringer Ingelheim, Bristol Myers Squibb, Chugai, Janssen, Lilly, MEDAC, Novartis, Pfizer, Roche, Consultant of: Boehringer Ingelheim, Bristol Myers Squibb, Chugai, Lilly, Pfizer, Roche, Grant/research support from: Bristol Myers Squibb, Galapagos, Pfizer, Jeffrey Sparks Consultant of: AbbVie, Amgen, Boehringer Ingelheim, Bristol Myers Squibb, Gilead, Inova Diagnostics, Janssen, Optum, Pfizer, Grant/research support from: Bristol Myers Squibb, Aryeh Fischer Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Leo Chen Consultant of: Bristol Myers Squibb, Employee of: Syneos Health, Karissa Lozenski Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Stephanie Dahan Shareholder of: Bristol Myers Squibb, Consultant of: Otsuka Pharmaceutical, Grant/research support from: Bristol Myers Squibb, Janssen Pharmaceuticals, Employee of: Bristol Myers Squibb, Mark Chaballa Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Wayne Little Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb.